Changes in insulin resistance following bariatric surgery: role of caloric restriction and weight loss

Misalignment of Circadian Rhythms in Diet-Induced Obesity

The biological clocks of the circadian timing system coordinate cellular and physiological processes and synchronize them with daily cycles. While the central clock in the suprachiasmatic nucleus (SCN) is mainly synchronized by the light/dark cycles, the peripheral clocks react to other stimuli, including the feeding/fasting state, nutrients, sleep-wake cycles, and physical activity. During the disruption of circadian rhythms due to genetic mutations or social and occupational obligations, incorrect arrangement between the internal clock system and environmental rhythms leads to the development of obesity. Desynchronization between the central and peripheral clocks by altered timing of food intake and diet composition leads to uncoupling of the peripheral clocks from the central pacemaker and to the development of metabolic disorders. The strong coupling of the SCN to the light-dark cycle creates a situation of misalignment when food is ingested during the "wrong" time of day. Food-anticipatory activity is mediated by a self-sustained circadian timing, and its principal component is a food-entrainable oscillator. Modifying the time of feeding alone greatly affects body weight, whereas ketogenic diet (KD) influences circadian biology, through the modulation of clock gene expression. Night-eating behavior is one of the causes of circadian disruption, and night eaters have compulsive and uncontrolled eating with severe obesity. By contrast, time-restricted eating (TRE) restores circadian rhythms through maintaining an appropriate daily rhythm of the eating-fasting cycle. The hypothalamus has a crucial role in the regulation of energy balance rather than food intake. While circadian locomotor output cycles kaput (CLOCK) expression levels increase with high-fat diet-induced obesity, peroxisome proliferator-activated receptor-alpha (PPARα) increases the transcriptional level of brain and muscle aryl hydrocarbon receptor nuclear translocator (ARNT)-like 1 (BMAL1) in obese subjects. In this context, effective timing of chronotherapies aiming to correct SCN-driven rhythms depends on an accurate assessment of the SCN phase. In fact, in a multi-oscillator system, local rhythmicity and its disruption reflects the disruption of either local clocks or central clocks, thus imposing rhythmicity on those local tissues, whereas misalignment of peripheral oscillators is due to exosome-based intercellular communication.Consequently, disruption of clock genes results in dyslipidemia, insulin resistance, and obesity, while light exposure during the daytime, food intake during the daytime, and sleeping during the biological night promote circadian alignment between the central and peripheral clocks. Thus, shift work is associated with an increased risk of obesity, diabetes, and cardiovascular diseases because of unusual eating times as well as unusual light exposure and disruption of the circadian rhythm.

Bariatric Surgery in Obesity: Metabolic Quality Analysis and Comparison of Surgical Options

Obesity is a constantly growing health problem which reduces quality of life and life expectancy. Bariatric surgery (BS) for obesity is considered when all other conservative treatment modalities have failed. Comparison of the multidisciplinary programs with BS regarding to the weight loss showed that substantial and durable weight reduction have been achieved only with bariatric surgical treatments. Although laparoscopic sleeve gastrectomy is the most popular BS, it has high long-term failure rates, and it is claimed that one of every three patients will undergo another bariatric procedure within a 10-year period. Although BS provides weight loss and improvement of metabolic comorbidities, in long-term follow-up, weight gain is observed in half of the patients, while decrease in bone mass and nutritional deficiencies occur in up to 90%. Moreover, despite significant weight loss, several psychological aspects of patients are worsened in comparison to preoperative levels. Nearly one-fifth of postoperative patients with "Loss-of-eating control" meet food addiction criteria. Therefore, the benefits of weight loss following bariatric procedures alone are still debated in terms of the proinflammatory and metabolic profile of obesity.

An Imbalance of Pathophysiologic Factors in Late Postprandial Hypoglycemia Post Bariatric Surgery: A Narrative Review

With a rise in obesity and more patients opting for bariatric surgery, it becomes crucial to understand associated complications like postprandial hypoglycemia (PPH). After bariatric surgery, significant changes are seen in insulin sensitivity, beta cell function, glucagon-like peptide 1 (GLP-1) levels, the gut microbiome, and bile acid metabolism. And in a small subset of patients, exaggerated imbalances in these functional and metabolic processes lead to insulin-glucose mismatch and hypoglycemia. The main treatment for PPH involves dietary modifications. For those that do not respond, medications or surgical interventions are considered to reverse some of the imbalances. We present a few case reports of patients that safely tolerated GLP-1 agonists. However, larger randomized control trials are needed to further characterize PPH and understand its treatment.

Hypoglycemic Effect of Exopolysaccharide from Lactiplantibacillus plantarum JLAU103 on Streptozotocin and High-Fat Diet-Induced Type 2 Diabetic Mice

Two doses (300 mg/kg bw and 600 mg/kg bw) of the Lactiplantibacillus plantarum JLAU103 exopolysaccharide (EPS103) were orally administered to a type 2 diabetic (T2DM) mouse model induced by streptozotocin and a high-fat diet. The hypoglycemic, hypolipidemic and neuroprotective effects of EPS103 on T2DM mice were evaluated. The results indicated that administration of EPS103 could alleviate insulin resistance, reduce the levels of fasting blood glucose, glycosylated hemoglobin A1c, leptin and fasting serum insulin, improve glucose tolerance, protect pancreas and liver, and modulate blood lipid disorders. EPS103 promoted hepatic glycogen synthesis by upregulating the phosphorylation of GSK3β. Meanwhile, it upregulated the phosphorylation of IRS-1, PI3K and Akt, as well as the expression of IRS-2 and GLUT4, and downregulated the expression of PEPCK, G6Pase and PGC-1α, indicating that EPS103 promotes the uptake and transport of glucose and inhibits gluconeogenesis, which might be related to the activation of the IRS-1/PI3K/Akt pathway. Additionally, EPS103 can protect against brain nerve damage through improving oxidative stress injury, restoring the expression of IRS-2, alleviating neuronal apoptosis and inhibiting inflammation in the hippocampus of T2DM mice. Taken together, our results demonstrated that EPS103 may be a potential therapeutic agent for the treatment of T2DM.

Supporting patients to achieve remission of type 2 diabetes

The incidence of diabetes mellitus is increasing, with a new diagnosis made every two minutes in the UK. Previously, it was believed that type 2 diabetes was progressive and irreversible. However, research has shown that it may be possible to reverse type 2 diabetes - termed remission - in people who achieve significant weight loss (>10% of their body weight) and who have had the condition for less than ten years. Weight loss should be the primary goal of treatment for people newly diagnosed with type 2 diabetes, and nurses have an important role in supporting this. This article discusses some of the research on remission of type 2 diabetes and dietary approaches to weight loss. It also considers the role of the nurse in supporting patients with this condition to achieve and sustain weight loss.

PM2.5 induced weight loss of mice through altering the intestinal microenvironment: Mucus barrier, gut microbiota, and metabolic profiling

The experimental evidences linking PM_2.5 exposure to weight status disorder and the associated mechanisms were lacked. Here, we demonstrated exposure of 198.52 μg/m³ PM_2.5 (Baoji city, China) for 40 days induced body weight loss of male Balb/C mice, and then increased after 14-day recovery. Correspondingly, gut microbiota dysbiosis, ileum metabolism alterations, and histopathological changes of liver and ileum elucidated the underlying mechanism. The richness and function modules of flora in feces significantly reduced after exposure, and the ratios of Bacteroidetes/Firmicutes reduced from 1.58 to 0.79. At genus level, Lactobacillus and Clostridium increased markedly, while Bacteroides and Parabacteroides decreased at day 40. After recovery, Oscillospira became the dominant genus. Additionally, the key metabolites in the ileum mediated by PM_2.5 identified by metabolomics included arachidonic acid, prostaglandin H₂, prostaglandin F_2α, 5(S)-HPETE, AMP, and deoxyadenosine. Accordingly, conjoint analysis between the gut micorbiota and metabolic profiling revealed suppression of Arachidonic acid metabolism, linoleic acid metabolism, and PPAR signaling pathway and stimulation of ABC transporters might contribute to the liver injury, ileum inflammation, and then weight loss of mice. Our findings suggested PM_2.5 affected weight status of mice by meditating intestinal microenvironment, and provided new insight for further diagnosis of the air pollution dependent disease.

The Effect and Mechanism of Duodenal-Jejunal Bypass to Treat Type 2 Diabetes Mellitus in a Rat Model

OBJECTIVES

Bariatric surgery can treat obesity and T2DM, but the specific mechanism is unknown. This study investigated the effect and possible mechanism of duodenal-jejunal bypass (DJB) to treat T2DM.

METHODS

A T2DM rat model was established using a high-fat, high-sugar diet and a low dose of streptozotocin. DJB surgery and a sham operation (SO) were performed to analyze the effects on glucose homeostasis, lipid metabolism, and inflammation changes. Furthermore, the glucagon-like peptide-1 (GLP-1) in the ileum and the markers of endoplasmic reticulum stress (ERS) in the pancreas were examined after the surgery. The insulinoma cells (INS-1) were divided into three groups; group A was cultured with a normal sugar content (11.1 mmol/L), group B was cultured with fluctuating high glucose (11.1 mmol/L alternating with 33.3 mmol/L), and group C was cultured with fluctuating high glucose and exendin-4 (100 nmol/L). The cells were continuously cultured for 7 days in complete culture medium. The viability of the INS-1 cells was then investigated using the MTT method, apoptosis was detected by flow cytometry, and the ERS markers were detected by Western blot.

RESULTS

The blood glucose, lipids, insulin, and TNF-α were significantly elevated in the T2DM model. A gradual recovery was observed in the DJB group. GLP-1 expression in the distal ileum of the DJB group was significantly higher than that in the T2DM control group (DM) and the SO group (p < 0.05), and the markers of ERS expression in the pancreases of the DJB group decreased significantly more than those of groups DM and SO (p < 0.05). Compared with group A, the cell viability in group B was decreased, and the ERS and apoptosis were increased (p < 0.05). However, compared with group B, the cell viability in group C was improved, and the ERS and apoptosis declined (p < 0.05).

CONCLUSIONS

DJB can be used to treat T2DM in T2DM rats. The mechanism may be that the DJB stimulates the increased expression of GLP-1 on the far side of the ileum, and then, GLP-1 inhibits ERS in the pancreas, reducing the apoptosis of β cells to create a treatment effect in the T2DM rats.

Intravital imaging of islet Ca2+ dynamics reveals enhanced β cell connectivity after bariatric surgery in mice

Bariatric surgery improves both insulin sensitivity and secretion and can induce diabetes remission. However, the mechanisms and time courses of these changes, particularly the impact on β cell function, are difficult to monitor directly. In this study, we investigated the effect of Vertical Sleeve Gastrectomy (VSG) on β cell function in vivo by imaging Ca²⁺ dynamics in islets engrafted into the anterior eye chamber. Mirroring its clinical utility, VSG in mice results in significantly improved glucose tolerance, and enhanced insulin secretion. We reveal that these benefits are underpinned by augmented β cell function and coordinated activity across the islet. These effects involve changes in circulating GLP-1 levels which may act both directly and indirectly on the β cell, in the latter case through changes in body weight. Thus, bariatric surgery leads to time-dependent increases in β cell function and intra-islet connectivity which are likely to contribute to diabetes remission.

Biliopancreatic Limb Length of Small Intestinal Bypass in Non-obese Goto-Kakizaki (GK) Rats Correlates with Gastrointestinal Hormones, Adipokines, and Improvement in Type 2 Diabetes

BACKGROUND

The purpose of this study was to explore the effects on type 2 diabetes, gastrointestinal hormones, and adipokines after the small intestinal bypass of different biliopancreatic limb (BPL) lengths in non-obese type 2 diabetic rats.

METHOD

Small intestinal bypass with the BPL length at 10cm, 20cm, 30cm, and 40cm, respectively, and sham surgery were performed in non-obese GK rats. Fasting serum was collected at 2 days preoperatively and 1, 3, 6, and 9 weeks postoperatively. Body weight and fasting blood glucose (FBG) were measured during the experiment. Glycated hemoglobin (GHb), fasting insulin (FINS), C-peptide, ghrelin, leptin, adiponectin, and somatostatin were measured postoperatively.

RESULT

Rats with a bypassed length of 40cm died within 5-9 weeks. No statistically significant was observed in body weight between the sham group and the bypass groups at the 9th week postoperatively. FBG, GHb, FINS, C-peptide, and HOMA-IR in the bypass groups were lower than those in the sham group postoperatively and were negatively correlated with BPL length. Ghrelin and leptin declined compared with preoperative but were not associated with BPL length. Adiponectin of the bypass groups increased after operation and was positively correlated with BPL length. Somatostatin remained stable among groups during the experiment.

CONCLUSION

Ghrelin and leptin of non-obese GK rats decreased postoperatively without a linear relationship with the BPL length, while adiponectin increased with positively correlation with the BPL length. In addition, somatostatin remained steady after small intestinal bypass. Further studies are expected to confirm the effect of the BPL length of small intestinal bypass on gastrointestinal hormones and adipokines.

Protective Effects of Bariatric Surgery on Kidney Functions by Inhibiting Oxidative Stress Responses Through Activating PPARα in Rats With Diabetes

Objective

The aim of this study was to explore the protective effects and the regulatory mechanisms of bariatric surgery on kidney injury in diabetic rats.

Methods

We established a useful type 2 diabetic rat model using high-fat and high-sugar diet feeding following low-dose streptozotocin (STZ) treatment. Sprague–Dawley (SD) rats were randomly divided into the following groups: control (Con) group, diabetic nephropathy (DN) group, and duodenal–jejunal bypass (DJB) surgery group. The food intake and body weight of rats were monitored and the glucose tolerance test (OGTT) test was performed every 2 weeks. The glomerular filtration rate (GFR) and urinary albumin excretion rate (UAFR) were measured to assess renal function. Hematoxylin–eosin (H&E), periodic acid–Schiff (PAS), and Masson staining were used to evaluate renal histopathological changes. TUNEL assay was performed to detect cell apoptosis. The expressions of oxidative stress factors and inflammatory factors in the renal tissues of rats were detected by ELISA. The expressions of PPARα, reactive oxygen species (ROS), and NF-κB were detected by immunofluorescence. For in vitro experiment, HK2 cells cultured with high glucose were treated with PPARα agonist, PPARα antagonist, and adenosine 5′-monophosphate (AMP)-activated protein kinase (AMPK) agonist. The expressions of AMPK/PPARα/NF-κB signaling pathway-related proteins were detected by Western blot.

Results

Bariatric surgery improved the glucose tolerance of DN rats. The GFR was decreased, the promotion of urinary albumin excretion rate (UAER) was inhibited, and the renal injury was alleviated. The extracellular matrix fraction was decreased and the renal function was improved. Meanwhile, bariatric surgery activates PPARα, inhibits ROS release, reduces oxidative stress injury, and reduces renal cell apoptosis. In vitro experiment results showed that the AMPK activator could activate PPARα, downregulate NF-κB, and inhibit inflammatory response. The phosphorylation of AMPK was inhibited by PPARα antagonism.

Conclusion

Bariatric surgery can activate PPARα, inhibit oxidative stress injury, and improve glucose metabolism and renal function in DN rats.

Type 2 diabetes and viral infection; cause and effect of disease

The recent pandemic of COVID-19 has made abundantly clear that Type 2 diabetes (T2D) increases the risk of more frequent and more severe viral infections. At the same time, pro-inflammatory cytokines of an anti-viral Type-I profile promote insulin resistance and form a risk factor for development of T2D. What this illustrates is that there is a reciprocal, detrimental interaction between the immune and endocrine system in the context of T2D. Why these two systems would interact at all long remained unclear. Recent findings indicate that transient changes in systemic metabolism are induced by the immune system as a strategy against viral infection. In people with T2D, this system fails, thereby negatively impacting the antiviral immune response. In addition, immune-mediated changes in systemic metabolism upon infection may aggravate glycemic control in T2D. In this review, we will discuss recent literature that sheds more light on how T2D impairs immune responses to viral infection and how virus-induced activation of the immune system increases risk of development of T2D.

Development of cancer after bariatric surgery

BACKGROUND

Although bariatric surgery has been associated with a reduction in risk of obesity-related cancer, data on the effect of bariatric interventions on other cancers are limited.

OBJECTIVES

This study aimed to examine the relationship between bariatric interventions and the incidence of various cancers after bariatric surgery.

SETTING

Administrative statewide database.

METHODS

The New York Statewide Planning and Research Cooperative System database was used to identify all adult patients diagnosed with obesity between 2006 and 2012 and patients who underwent bariatric procedures without preexisting cancer diagnosis and alcohol or tobacco use. Subsequent cancer diagnoses were captured up to 2016. Multivariable proportional subdistribution hazard regression analysis was performed to compare the risk of having cancer among obese patients with and without bariatric interventions.

RESULTS

We identified 71,000 patients who underwent bariatric surgery and 323,197 patients without a bariatric intervention. Patients undergoing bariatric surgery were less likely to develop both obesity-related cancer (hazard ratio.91; 95% confidence interval, .85-.98; P = .013) and other cancers (hazard ratio .81; 95% confidence interval, .74-.89; P < .0001). Patients undergoing Roux-en-Y gastric bypass had a lower risk of developing cancers that are considered nonobesity related (hazard ratio .59; 95% confidence interval, .42-.83; P = .0029) compared with laparoscopic sleeve gastrectomy.

CONCLUSIONS

Bariatric surgery is associated with a decreased risk of obesity-related cancers. More significantly, we demonstrated the relationship between bariatric surgery and the reduction of the risk of some previously designated nonobesity-related cancers, as well. Reclassification of nonobesity-related cancers and expansion of bariatric indications for reducing the risk of cancer may be warranted.

Adiponectin receptor fragmentation in mouse models of type 1 and type 2 diabetes

The protein hormone adiponectin regulates glucose and fatty acid metabolism by binding to two PAQR-family receptors (AdipoR1 and AdipoR2). Both receptors feature a C-terminal segment which is released by proteolysis to form a freely circulating C-terminal fragment (CTF) found in the plasma of normal individuals but not in some undefined diabetes patients. The AdipoR1-CTF_344–376 is a competitive inhibitor of tumor necrosis factor α cleavage enzyme (TACE) but it contains a shorter peptide domain (AdipoR1 CTF_351–362) that is a strong non-competitive inhibitor of insulin-degrading enzyme (IDE). The link between adiponectin receptor fragmentation and diabetes pathology is unclear but could lead to new therapeutic strategies. We therefore investigated physiological variations in the concentrations of CTF in non-obese diabetic (NOD/ShiLtJ) mice and C57BL/6 mice with diet-induced obesity (DIO) as models of diabetes types 1 and 2, respectively. We tested for changes in adiponectin receptor signaling, immune responses, disease progression, and the abundance of neutralizing autoantibodies. Finally, we administered exogenous AdipoR1-CTF peptides either containing or lacking the IDE-binding domain. We observed the more pronounced CTF shedding in the TACE-active NOD mice, which represents an inflammatory autoimmune phenotype, but fragmentation was also observed to a lesser extent in the DIO model. Autoantibodies to CTF were detected in both models. Neither exogenous CTF peptide affected IgG-CTF plasma levels, body weight or the conversion of NOD mice to diabetes. The pattern of AdipoR1 fragmentation and autoantibody production under physiological conditions of aging, DIO, and autoimmune diabetes therefore provides insight into the association adiponectin biology and diabetes.

Macronutrient-Mediated Inflammation and Oxidative Stress: Relevance to Insulin Resistance, Obesity, and Atherogenesis

CONTEXT

The intake of macronutrients as components of a Western dietary pattern leads to oxidative stress and inflammation.

EVIDENCE ACQUISITION

Data were largely retrieved from our previous and most recent work. PubMed and Google Scholar were searched for recent articles on the effect of macronutrients/dietary intake on inflammation, insulin resistance, obesity, and atherogenesis. The most relevant, high-quality articles were included in our review.

EVIDENCE SYNTHESIS

Our previous work has demonstrated the molecular mechanisms of macronutrient-mediated oxidative stress and inflammation. With the induction of inflammation, proinflammatory molecules potentially interfere with insulin signal transduction, thus causing insulin resistance. In addition, other molecules promote atherogenic inflammation. More recently, our work has also shown that certain foods are noninflammatory or anti-inflammatory and thus, do not interfere with insulin signaling. Finally, as obesity is induced by chronic excessive caloric intake, it is characterized by an increase in the expression of proinflammatory molecules, which are induced acutely by a Western diet. Caloric restriction, including fasting, is associated with a reduction in oxidative and inflammatory stress.

CONCLUSIONS

This review summarizes and attempts to provide an up-to-date profile of the molecular mechanisms involved in macronutrient-mediated oxidative/inflammatory stress and its potential consequences. An understanding of these underlying mechanisms is crucial for making appropriate dietary choices.

Roux-en-Y-Bariatric Surgery Reduces Markers of Metabolic Syndrome in Morbidly Obese Patients

Background

Obesity is closely linked to increased markers of metabolic syndrome and development of diabetes. Roux-en-Y bariatric surgery reduces hyperinsulinemia and improves insulin sensitivity and hence benefits morbidly obese patients.

Aim

To determine changes in markers of metabolic syndrome, pancreatic function, and hepatic insulin sensitivity in patients before and 1 year after undergoing Roux-en-Y gastric bypass surgery.

Methods

We enrolled 43 consecutive patients in a single center. Markers for metabolic syndrome included proinsulin, insulin, C-peptide, liver enzymes, and serum levels of selected microRNAs hsa-miR-122, hsa-miR-130, hsa-miR-132, and hsa-miR-375.

Results

After surgery, all patients showed a significant 37% drop of body mass index (p < 0.001). Furthermore, proinsulin (59% reduction, p < 0.001), insulin (76% reduction, p < 0.001), and C-peptide (56% reduction, p < 0.001) were all reduced 1 year after surgery. Using the hepatic insulin clearance score, we determined a significant increase in hepatic insulin clearance after surgery (76% increase, p < 0.001). Especially diabetic patients showed a marked 2.1-fold increase after surgery. Hepatic enzymes ALT (35% reduction, p = 0.002) and γGT (48% reduction, p < 0.001) were significantly reduced in all patients with similar improvement in diabetic and non-diabetic patients. miRNAs hsa-miR-122, hsa-miR-130, and hsa-miR-132 were all significantly reduced whereas hsa-miR-375 was increased after gastric bypass surgery (p < 0.001 for all miRNAs).

Conclusion

Both liver and pancreatic stress parameters were reduced significantly 1 year after Roux-en-Y gastric bypass surgery suggesting an overall amelioration of the metabolic syndrome in all patients regardless of previous health status.

Preserving Duodenal-Jejunal (Foregut) Transit Does Not Impair Glucose Tolerance and Diabetes Remission Following Gastric Bypass in Type 2 Diabetes Sprague-Dawley Rat Model

BACKGROUND

Possible mechanisms underlying diabetes remission following Roux-en-Y gastric bypass (RYGB) include eradication of putative factor(s) with duodenal-jejunal bypass.

OBJECTIVE

The objective of this study is to observe the effects of duodenal-jejunal transit on glucose tolerance and diabetes remission in gastric bypass rat model.

METHOD

In order to verify the effect of duodenal-jejunal transit on glucose tolerance and diabetes remission in gastric bypass, 22 type 2 diabetes Sprague-Dawley rat models established through high-fat diet and low-dose streptozotocin (STZ) administered intraperitoneally were assigned to one of three groups: gastric bypass with duodenal-jejunal transit (GB-DJT n = 8), gastric bypass without duodenal-jejunal transit (RYGB n = 8), and sham (n = 6). Body weight, food intake, blood glucose, as well as meal-stimulated insulin, and incretin hormone responses were assessed to ascertain the effect of surgery in all groups. Oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) were conducted three and 7 weeks after surgery.

RESULTS

Comparing our GB-DJT to the RYGB group, we saw no differences in the mean decline in body weight, food intake, and blood glucose 8 weeks after surgery. GB-DJT group exhibited immediate and sustained glucose control throughout the study. Glucagon-like peptide 1 (GLP-1) and gastric inhibitory polypeptide (GIP) levels were also significantly increased from preoperative level in the GB-DJT group (p < 0.05). Insulin and GLP-1 area under curve (AUC) as well as improved glycemic excursion on OGTT did not differ between GB-DJT and RYGB groups. Outcomes with sham operation did not differ from preoperative level.

CONCLUSION

Preserving duodenal-jejunal transit does not impede glucose tolerance and diabetes remission after gastric bypass in type-2 diabetes Sprague-Dawley rat model.

Correlation between Body Mass Index and Homa Index in Bariatric Patients

Background and aims: Overweight and obese individuals are prone to an insulin resistance status assessed in the present study by the HOMA index ("Homeostasis model assessment"). This prospective study assessed the body mass index (BMI) and the insulin resistance status (HOMA index) in obese patients after bariatric surgery (gastric sleeve, gastric by-pass).

Material and Methods: The study included 48 patients who were assessed before the bariatric surgery and at 6 months thereafter. The assessment included the body mass index (BMI) and the HOMA index before meal.

Results: There was a significant positive correlation between BMI and HOMA index, mostly between weight loss and improvement in insulin resistance status (rho = 0.308, p = 0.0335).

Conclusions: BMI decreases significantly after bariatric surgery, which correlates positively with an improvement in insulin resistance status.

Sleeve gastrectomy rapidly enhances islet function independently of body weight

Bariatric surgeries including vertical sleeve gastrectomy (VSG) ameliorate obesity and diabetes. Weight loss and accompanying increases to insulin sensitivity contribute to improved glycemia after surgery; however, studies in humans also suggest weight-independent actions of bariatric procedures to lower blood glucose, possibly by improving insulin secretion. To evaluate this hypothesis, we compared VSG-operated mice with pair-fed, sham-surgical controls (PF-Sham) 2 weeks after surgery. This paradigm yielded similar postoperative body weight and insulin sensitivity between VSG and calorically restricted PF-Sham animals. However, VSG improved glucose tolerance and markedly enhanced insulin secretion during oral nutrient and i.p. glucose challenges compared with controls. Islets from VSG mice displayed a unique transcriptional signature enriched for genes involved in Ca2+ signaling and insulin secretion pathways. This finding suggests that bariatric surgery leads to intrinsic changes within the islet that alter function. Indeed, islets isolated from VSG mice had increased glucose-stimulated insulin secretion and a left-shifted glucose sensitivity curve compared with islets from PF-Sham mice. Isolated islets from VSG animals showed corresponding increases in the pulse duration of glucose-stimulated Ca2+ oscillations. Together, these findings demonstrate a weight-independent improvement in glycemic control following VSG, which is, in part, driven by improved insulin secretion and associated with substantial changes in islet gene expression. These results support a model in which β cells play a key role in the adaptation to bariatric surgery and the improved glucose tolerance that is typical of these procedures.

The relationship between employment status and insulin resistance in the Korean elderly population

BACKGROUND/AIMS

This study aimed to investigate the relationship between employment status and insulin resistance in the Korean elderly population.

METHODS

The study included 2325 healthy participants (862 men and 1463 women) who did not have diabetes, were 60-74 years old, and participated in the 2007-2010 Korea National Health and Nutrition Examination Survey. Their employment status was categorized as employed or unemployed. The homeostasis model assessment of insulin resistance (HOMA-IR) was used to assess insulin sensitivity. Insulin resistance was defined as values greater than the 75th percentile of the HOMA-IR (> 2.67 in men and > 2.87 in women).

RESULTS

Mean HOMA-IR values were significantly higher for both sexes in the unemployed group than in the employed group. Compared with the unemployed group, the odds ratios (95% confidence intervals) for insulin resistance in the employed group were 0.55 (0.34-0.87) in men and 0.68 (0.47-0.98) in women after adjusting for confounders.

CONCLUSIONS

Being employed was significantly associated with a lower risk of insulin resistance in the Korean elderly population. These findings suggest that insulin sensitivity could be increased by increasing physical activity through occupational activities in the elderly population.

The Role of Laparoscopic Mini-Gastric Bypass in Management of Metabolic Syndrome

OBJECTIVE

The study was performed to evaluate the technique of laproscopic minigastric bypass for metabolic syndrome patients.

STUDY DESIGN

The patients were enrolled in a combined prospective study and had a retrospectively gathered outcome analysis.

PATIENT AND METHODS

The study includes thirty patients; 24 females and 6 males suffering from metabolic syndrome with a mean age of 33.15 ± 10.17 years (range, 20-59), who fulfilled the criteria for bariatric surgery with BMI >35 with associated co-morbidities, all patients underwent laparoscopic mini-gastric bypass.

RESULTS

BMI and WC were significantly reduced post-operatively; also co-morbidities as DM, hypertension and dyslipidemia were resolved or controlled. The mean operative time was 90 ± 12.6 min (range, 80-120). No mortality was reported within 30 days of surgery.

CONCLUSION

Laparoscopic mini gastric bypass is an effective procedure for the treatment of obesity, HTN, type 2 DM and dyslipidemia, technically feasible, safe operation with a low rate of major postoperative complications.

Inflammatory Cytokine Profiles in Visceral and Subcutaneous Adipose Tissues of Obese Patients Undergoing Bariatric Surgery Reveal Lack of Correlation With Obesity or Diabetes

Population studies have linked insulin resistance to systemic low-grade chronic inflammation and have reported elevated levels of inflammatory cytokines such as TNFα, IL-1β and IL-6, individually or in certain combinations, in adipose tissues or in the serum. We undertook this comprehensive study to simultaneously evaluate the expression of several pro-inflammatory and anti-inflammatory cytokines in serum and in the visceral and subcutaneous adipose tissues from obese patients undergoing bariatric surgery. We observed that several inflammatory cytokines implicated in obesity-associated inflammation showed no significant difference in protein or gene expression between obese patients with or without diabetes and control groups. IL1B gene expression was significantly elevated in the visceral adipose tissues of obese patients, but did not correlate with their diabetes status. Despite the significant increase in IL1B expression in the obese group, a significant proportion of obese patients did not express TNFA, IL1B or IL6 in visceral adipose tissues. Certain inflammatory cytokines showed correlation with the chemokine CCL2 and VEGF-A in visceral adipose tissues. Our findings suggest that the inflammatory cytokine profile in metabolic syndrome is more complex than what is currently perceived and that chronic inflammation in obese patients likely results from incremental contribution from different cytokines and possibly other inflammatory mediators from within and outside the adipose tissues. It is possible that this obesity associated chronic inflammation is not predicted by a single mediator, but rather includes a large spectrum of possible profiles.

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Visceral and subcutaneous adipose tissues do not express similar pattern of cytokines.

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VAT and SAT tissues from 30% of the obese patients do not express TNFA, IL6 or IL1B.

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Protein levels and gene expression do not necessarily correlate in VAT or SAT.

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The expression pattern of inflammatory mediators may present a larger spectrum than predicted from animal models.

Obesity, type 2 diabetes and cardiometabolic diseases are associated with a low-grade chronic inflammation. Various inflammatory mediators have been shown to mediate this inflammation. In this study we analyzed the expression of many of these inflammatory mediators in the visceral and subcutaneous adipose tissues obtained from patients undergoing bariatric surgery. Our results suggest that the profile of inflammatory mediators expressed in adipose tissue is diverse and varies from one patient to another.

A randomised controlled trial of a duodenal-jejunal bypass sleeve device (EndoBarrier) compared with standard medical therapy for the management of obese subjects with type 2 diabetes mellitus

INTRODUCTION

The prevalence of obesity and obesity-related diseases, including type 2 diabetes mellitus (T2DM), is increasing. Exclusion of the foregut, as occurs in Roux-en-Y gastric bypass, has a key role in the metabolic improvements that occur following bariatric surgery, which are independent of weight loss. Endoscopically placed duodenal-jejunal bypass sleeve devices, such as the EndoBarrier (GI Dynamics, Lexington, Massachusetts, USA), have been designed to create an impermeable barrier between chyme exiting the stomach and the mucosa of the duodenum and proximal jejunum. The non-surgical and reversible nature of these devices represents an attractive therapeutic option for patients with obesity and T2DM by potentially improving glycaemic control and reducing their weight.

METHODS AND ANALYSIS

In this multicentre, randomised, controlled, non-blinded trial, male and female patients aged 18-65 years with a body mass index 30-50 kg/m² and inadequately controlled T2DM on oral antihyperglycaemic medications (glycosylated haemoglobin (HbA1c) 58-97 mmol/mol) will be randomised in a 1:1 ratio to receive either the EndoBarrier device (n=80) for 12 months or conventional medical therapy, diet and exercise (n=80). The primary outcome measure will be a reduction in HbA1c by 20% at 12 months. Secondary outcome measures will include percentage weight loss, change in cardiovascular risk factors and medications, quality of life, cost, quality-adjusted life years accrued and adverse events. Three additional subgroups will investigate the mechanisms behind the effect of the EndoBarrier device, looking at changes in gut hormones, metabolites, bile acids, microbiome, food hedonics and preferences, taste, brain reward system responses to food, eating and addictive behaviours, body fat content, insulin sensitivity, and intestinal tissue gene expression.

TRIAL REGISTRATION NUMBER

ISRCTN30845205, ClinicalTrials.gov Identifier NCT02459561.

Cross-Talk Between Bile Acids and Gastro-Intestinal and Thermogenic Hormones: Clues from Bariatric Surgery

Obesity is rapidly increasing and has reached epidemic features worldwide. It´s linked to insulin resistance, systemic low-grade inflammation and common pathogenic pathways with a number of comorbidities (including cancer), leading to high mortality rates. Besides change of lifestyles (diet and physical exercise) and pharmacological therapy, bariatric surgery is able to rapidly improve several metabolic and morphologic features associated with excessive fat storage, and currently represents an in vivo model to study the pathogenic mechanisms underlying obesity and obesity-related complications. Studies on obese subjects undergoing bariatric surgery find that the effects of surgery are not simply secondary to gastric mechanical restriction and malabsorption which induce body weight loss. In fact, some surgical procedures positively modify key pathways involving the intestine, bile acids, receptor signaling, gut microbiota, hormones and thermogenesis, leading to systemic metabolic changes. Furthermore, bariatric surgery represents a suitable model to evaluate the gene-environment interaction and some epigenetic mechanisms linking obesity and insulin resistance to metabolic diseases.

Seven Years of Mini-Gastric Bypass in Type II Diabetes Patients with a Body Mass Index <35 kg/m(2)

BACKGROUND

Mini-gastric bypass (MGB) is a safe, effective, and reversible procedure for patients with type II diabetes mellitus (T2DM) and morbid obesity. Less is known, however, about its long-term effects in patients with a body mass index (BMI) <35 kg/m(2).

METHODS

From February 2007 to February 2014, 1468 patients underwent MGB at our institution, including 983 with T2DM. Of these, 128 (82 women), of mean age 41.6 ± 10.2 years, had a BMI of 30-35 kg/m(2). Prospectively collected data were analyzed retrospectively. Factors assessed included disease duration, family history, medication use, remission, and biochemical indicators, including fasting plasma glucose, glycosylated hemoglobin (HbA1c), serum insulin, and C-peptide concentrations. Remission of T2DM was defined as HbA1c <6.0 % without medication.

RESULTS

Prior to surgery, patients had a mean BMI of 33.4 ± 3.3 kg/m(2), mean waist circumference of 104.5 ± 8.2 cm, mean C-peptide concentration of 3.4 ± 1.2 ng/ml, and mean T2DM duration of 6.5 ± 3.1 years. Within 6 months of MGB, 95 % of these patients had attained HbA1c <7 %. Complete remission rates at 1, 2, and 7 years were 64, 66, and 53 %, respectively. Mean HbA1c decreased from 10.7 ± 1.5 % at baseline to 6.2 ± 0.5% at 1 year, 5.4 ± 1.2 % at 3 years, and 5.7 ± 1.8 % at 7 years. No deaths occurred, but two (1.6 %) patients experienced major complications.

CONCLUSIONS

MGB provides good, long-term control of T2DM in patients with class I obesity. Early intervention results in higher remission rates.

Bile acids and bariatric surgery

Bariatric surgery, specifically Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG), are the most effective and durable treatments for morbid obesity and potentially a viable treatment for type 2 diabetes (T2D). The resolution rate of T2D following these procedures is between 40 and 80% and far surpasses that achieved by medical management alone. The molecular basis for this improvement is not entirely understood, but has been attributed in part to the altered enterohepatic circulation of bile acids. In this review we highlight how bile acids potentially contribute to improved lipid and glucose homeostasis, insulin sensitivity and energy expenditure after these procedures. The impact of altered bile acid levels in enterohepatic circulation is also associated with changes in gut microflora, which may further contribute to some of these beneficial effects. We highlight the beneficial effects of experimental surgical procedures in rodents that alter bile secretory flow without gastric restriction or altering nutrient flow. This information suggests a role for bile acids beyond dietary fat emulsification in altering whole body glucose and lipid metabolism strongly, and also suggests emerging roles for the activation of the bile acid receptors farnesoid x receptor (FXR) and G-protein coupled bile acid receptor (TGR5) in these improvements. The limitations of rodent studies and the current state of our understanding is reviewed and the potential effects of bile acids mediating the short- and long-term metabolic improvements after bariatric surgery is critically examined.

Does Bariatric Surgery Improve Obesity Associated Comorbid Conditions

Obesity is a constantly growing health problem which reduces quality of life and life expectancy. Bariatric surgery for obesity is taken into account when all other conservative treatment modalities have failed. Comparison of the multidisciplinary programs with bariatric surgery regarding to weight loss showed that substantial and durable weight reduction have been achieved only with bariatric surgical treatments. However, the benefits of weight loss following bariatric procedures are still debated regarding the pro-inflammatory and metabolic profile of obesity.

Common Channel Length in Bypass Surgery Does Not Impact T2DM in Diabetic Zucker Rats

INTRODUCTION

Metabolic surgery is known to impact glucose tolerance but the exact mechanism is still unclear. Based on recently-published data, especially the role of the hindgut may require redefinition.

METHODS

Either a loop duodeno-jejunostomy (DJOS) with exclusion of one third of total intestinal length, a loop duodeno-ileostomy (DiOS, exclusion of two thirds), or SHAM operation was performed in 9-week-old Zucker diabetic fatty rats. One, 3, and 6 months after surgery, an oral glucose tolerance test (OGTT) and glucose-stimulated hormone analyses were conducted. Body weight was documented weekly.

RESULTS

DJOS and DiOS animals showed significantly better glucose control in all OGTTs than the SHAM group (two-way ANOVA p < 0.0001). Body weight developed largely parallel in both intervention groups; SHAM animals had gained significantly less weight after 6 months (Mann-Whitney DJOS/DiOS vs. SHAM p < 0.05, DJOS vs. DiOS p > 0.05). Operative interventions had no impact on GLP-1 and GIP levels at any time point (Mann-Whitney p > 0.05 for all). DJOS/DiOS operations could preserve insulin production up to 6 months, while there was already a sharp decline of insulin levels in the SHAM group (Mann-Whitney: DJOS/DiOS vs. SHAM p < 0.05 for all time points). Additionally, insulin sensitivity was improved significantly 1 month postoperative in both intervention groups compared to SHAM (Mann-Whitney DJOS/DiOS vs. SHAM p < 0.05).

CONCLUSION

The data of the current study demonstrate a sharp amelioration of glucose control after duodenal exclusion with unchanged levels of GLP-1 and GIP. Direct or delayed hindgut stimulation had no impact on glucose control in our model.

Circadian Rhythms in Diet-Induced Obesity

The biological clocks of the circadian timing system coordinate cellular and physiological processes and synchronizes these with daily cycles, feeding patterns also regulates circadian clocks. The clock genes and adipocytokines show circadian rhythmicity. Dysfunction of these genes are involved in the alteration of these adipokines during the development of obesity. Food availability promotes the stimuli associated with food intake which is a circadian oscillator outside of the suprachiasmatic nucleus (SCN). Its circadian rhythm is arranged with the predictable daily mealtimes. Food anticipatory activity is mediated by a self-sustained circadian timing and its principal component is food entrained oscillator. However, the hypothalamus has a crucial role in the regulation of energy balance rather than food intake. Fatty acids or their metabolites can modulate neuronal activity by brain nutrient-sensing neurons involved in the regulation of energy and glucose homeostasis. The timing of three-meal schedules indicates close association with the plasma levels of insulin and preceding food availability. Desynchronization between the central and peripheral clocks by altered timing of food intake and diet composition can lead to uncoupling of peripheral clocks from the central pacemaker and to the development of metabolic disorders. Metabolic dysfunction is associated with circadian disturbances at both central and peripheral levels and, eventual disruption of circadian clock functioning can lead to obesity. While CLOCK expression levels are increased with high fat diet-induced obesity, peroxisome proliferator-activated receptor (PPAR) alpha increases the transcriptional level of brain and muscle ARNT-like 1 (BMAL1) in obese subjects. Consequently, disruption of clock genes results in dyslipidemia, insulin resistance and obesity. Modifying the time of feeding alone can greatly affect body weight. Changes in the circadian clock are associated with temporal alterations in feeding behavior and increased weight gain. Thus, shift work is associated with increased risk for obesity, diabetes and cardio-vascular diseases as a result of unusual eating time and disruption of circadian rhythm.

The role of obestatin in Roux-en-Y gastric bypass surgery in the obese, type 2 diabetes Zucker rat

AIMS

Roux-en-Y gastric bypass (RYGB) is a novel therapy for diabetes and the exact mechanisms of this procedure remain unclear. Obestatin is an important gut hormone. We aimed to explore the role of obestatin in the therapeutic mechanism of RYGB.

METHODS

Twenty obese Zucker rats and twenty Wistar rats were randomly assigned to two groups: RYGB and sham surgery. We evaluated plasma obestatin and insulin levels pre- and post-RYGB. Additionally, obestatin expression levels in the gastrointestinal tract were assessed using immunohistochemical staining.

RESULTS

In Zucker rats, plasma obestatin and insulin levels gradually increased after RYGB. At post-operation week 7, plasma levels of obestatin were higher in the RYGB group than the sham operation group, and fasting plasma insulin levels were significantly increased the in RYGB group compared with the sham operation group. Furthermore, we observed a positive relationship between obestatin and insulin plasma levels. Among 10 zucker rats, high expression of obestatin was only seen in the jejunum of 2 rats before the operation; however, high expression of obestatin was seen in the Roux limb of 8 rats and in the ileum of 7 rats after RYGB. The expression of obestatin was significantly higher in the intestine in the RYGB group than the sham operation group postoperatively.

CONCLUSIONS

We propose that obestatin maybe a potential mediator to improve glucose homeostasis after RYGB. The increase of obestatin secretion may be an important mechanism through which RYGB alleviates obesity and type 2 diabetes mellitus.

Immediate Metabolic Response Following Sleeve Gastrectomy in Obese Diabetics

BACKGROUND

Although laparoscopic sleeve gastrectomy (LSG) has been shown to have a long-term antidiabetic effect, little is known regarding the immediate response to surgery. This study's objective was to evaluate the glycemic and lipid metabolic response in the first postoperative week.

METHODS

The study included 21 obese diabetic participants. Glycemic markers, lipids, and hepatic function tests were measured just prior to surgery and at 1 week and 3 months postoperatively. Two participants were dropped prior to all measurements due to technical reasons, and two more were lost to follow-up.

RESULTS

At 1 week after surgery, compared to preoperative baseline, we found reduced hemoglobin A1c (7.63 to 7.31, P < 0.001), insulin (24.96 to 10.92, P < 0.05), and borderline significant homeostatic model assessment insulin resistance (HOMA-IR, 9.48 to 3.91, P > 0.05). Low-density lipoprotein (LDL) cholesterol increased and high-density lipoprotein (HDL) cholesterol decreased. Three months after surgery, hemoglobin A1c, insulin, and HOMA-IR continued to decrease (6.05, 7.11, and 1.92, respectively, P < 0.05), with hemoglobin A1c correlated to weight loss (P < 0.05). Triglycerides, triglyceride to HDL ratio, and total cholesterol to HDL ratio also decreased, but there was no significant change in LDL cholesterol or HDL versus presurgery levels. Reduced triglyceride levels were correlated with reduced alanine transaminase (ALT) and gamma-glutamyl transpeptidase (GGT) (P < 0.05).

CONCLUSIONS

LSG is associated with marked antidiabetic effects as early as 1 week after surgery, unrelated to weight loss. The antidiabetic effect improves at 3 months. Triglyceride reduction was associated with improved hepatic functions, but cholesterol did not show a meaningful reduction.

GLP-1: a mediator of the beneficial metabolic effects of bariatric surgery?

There has been increasing interest in the role that gut hormones may play in contributing to the physiological changes produced by certain bariatric procedures, such as Roux-en-Y gastric bypass and sleeve gastrectomy. Here, we review the evidence implicating one such gut hormone, glucagon-like peptide-1, as a mediator of the metabolic benefits of these two procedures.

A meta-analysis of 2-year effect after surgery: laparoscopic Roux-en-Y gastric bypass versus laparoscopic sleeve gastrectomy for morbid obesity and diabetes mellitus

Literature search was performed for bariatric surgery from inception to September 2013, in which the effects of laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic sleeve gastrectomy (LSG) on body mass index (BMI), percentage of excess weight loss (EWL%), and diabetes mellitus (DM) were compared 2 years post-surgery. A total of 9,756 cases of bariatric surgery from 16 studies were analyzed. Patients receiving LRYGB had significantly lower BMI and higher EWL% compared with those receiving LSG (BMI mean difference (MD) = -1.38, 95% confidence interval (CI) = -1.72 to -1.03; EWL% MD = 5.06, 95% CI = 0.24 to 9.89). Improvement rate of DM was of no difference between the two types of bariatric surgeries (RR = 1.05, 95% CI = 0.90 to 1.23). LRYGB had better long-term effect on body weight, while both LRYGB and LSG showed similar effects on DM.

A meta-analysis of short-term outcomes of patients with type 2 diabetes mellitus and BMI ≤ 35 kg/m2 undergoing Roux-en-Y gastric bypass

BACKGROUND

Roux-en-Y gastric bypass (RYGB) is effective for type 2 diabetes mellitus (T2DM) patients with a body mass index (BMI) >35 kg/m(2). It is unknown whether it benefits those with a BMI ≤ 35 kg/m(2). In the last decade, the effect of bariatric procedures on metabolic outcomes in individuals who underwent surgery outside National Institutes of Health (NIH) guidelines (BMI ≤ 35 kg/m(2)) was both interesting and controversial.

OBJECTIVE

We performed a systematic analysis evaluating the effect of RYGB for T2DM patients with a BMI ≤ 35 kg/m(2).

METHODS

We searched databases (Embase, Ovid, PubMed, China National Knowledge Infrastructure [CNKI], and Cochrane Library) and relevant journals between January 1980 and October 2013. Keywords used in electronic searching included 'diabetes', 'gastric bypass', 'BMI', and 'body mass index'. Inclusion criteria were as follows: (1) patients who underwent RYGB; (2) sample size ≥ 15; (3) patients with a BMI ≤ 35 kg/m(2); and (4) follow-up ≥ 12 months. Exclusion criteria were as follows: (1) data extracted from a database; (2) trials for sleeve gastrectomy; (3) trials for laparoscopic banding; (4) trials for bilio-pancreatic diversion; and (5) trials for duodenojejunal bypass. Participants and intervention type 2 diabetes patients with BMI ≤ 35 kg/m(2) who underwent RYGB. Two investigators reviewed all reported studies independently. Data were extracted according to previously defined endpoints. A meta-analysis was performed for these parameters, with homogeneity among different trials.

RESULTS

Nine articles fulfilled inclusion criteria. After 12 months, patients with T2DM had a significant decrease in their BMI postoperatively (p < 0.00001, weighted mean difference [WMD] -7.42, 95 % confidence interval [CI] -8.87 to -5.97), and remission of diabetes (glucose: p < 0.00001, WMD -59.87, 95 % CI -67.74 to -52.01; hemoglobin A1c p < 0.00001, WMD -2.76, 95 % CI -3.41 to -2.11). There were no deaths in all trials, and the complication rate was between 6.7 and 25.9 %. Mean length of hospital stay was 2.00 to 3.20 days, and mean operative time was from 72.8 to 112.0 min. In terms of study limitations, publication and selection bias were unavoidable. Trials with small sample sizes were excluded, which may lead to a selection bias.

CONCLUSION

RYGB was effective for T2DM patients with BMI ≤ 35 kg/m(2). Further clinical studies with long-term follow-up data are necessary to clarify this issue.

Predictors of remission of type 2 diabetes mellitus in obese patients after gastrointestinal surgery

BACKGROUND

Gastroenterology is a beneficial treatment of morbidly obese type 2 diabetes mellitus (T2DM). We aimed to identify the predictors for the treatment of T2DM obese patients.

METHODS

A retrospective study consisting of 531 patients undergoing laparoscopic gastric banding (LGB), laparoscopic mini-gastric bypass (LMGB) and laparoscopic sleeve gastrectomy (LSG) from January 2004 to May 2007 was performed. Patients with preoperative fasting serum glucose concentration of more than 126 mg/dl were diagnosed as T2DM. A postoperatively fasting serum glucose level of less than 110 mg/dl was considered to be remission of T2DM.

RESULTS

Of the 531 patients, 62 (11.6%) were diagnosed as T2DM, including 23 men and 39 women, with a mean age of 31.8 ± 9.2 years, and a mean body mass index (BMI) of 40.0 kg/m(2). The mean glucose at 3, 6, and 12 months after surgery were 100.1 mg/dl, 95.1 mg/dl and 91.8 mg/dl, respectively. The mean body weight loss one year after surgery was 9.4% for LGB, 31.4% for LSG and 37.1% for LMGB, respectively. Among these operation methods (LGB, LMGB and LSG), the BMI, body weight, waist circumference, serum lipid profile and serum factors associated with glucose metabolism were significantly different during the one-year postoperative follow-up. Remission rate of T2DM was achieved in 84.8%, 58.8% and 58.3% of patients for LMGB, LGB and LSG, respectively. The best operative method for the remission of T2DM was LMGB. Using an artificial neural network (ANN) data mining technique, waist circumference, operative methods and C-peptide were significantly predictors for the remission of T2 DM.

CONCLUSION

One year after gastrointestinal surgery, improvement of serum lipid profiles and serum data related to glucose metabolism in the different operative methods were noticed. LMGB seems to be the most effective procedure for the reduction of serum glucose levels compared with LAGB and LSG.

Efficacy of Laparoscopic Mini Gastric Bypass for Obesity and Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis

Background. Controversies on the utility of laparoscopic mini gastric bypass (LMGB) in weight loss and type 2 diabetes mellitus (T2DM) control still exist. Methods. We conducted a comprehensive literature search of PubMed, EMBASE, and Cochrane Library. Review Manager was used to perform the meta-analysis and the weighted mean difference (WMD) and/or odds ratio with 95% confidence interval (95% CI) were used to evaluate the overall size effect. Results. The literature search identified 16 studies for systematic review and 15 articles for meta-analysis. Compared with LAGB, LSG, and LRYGB, LMGB showed significant weight loss [WMD, −6.58 (95% CI, −9.37, −3.79), P < 0.01 (LAGB); 2.86 (95% CI, 1.40, 5.83), P = 0.004 (LSG); 10.33 (95% CI, 4.30, 16.36), P < 0.01 (LRYGB)] and comparable/higher T2DM remission results [86.2% versus 55.6%, P = 0.06 (LAGB); 89.1% versus 76.3%, P = 0.004 (LAGB); 93.4% versus 77.6%, P = 0.006 (LAGB)]; LMGB also had shorter learning curve and less operation time than LRYGB [WMD, −35.2 (95% CI, −46.94, −23.46)]. Conclusions. LMGB appeared to be effective in weight loss and T2DM remission and noninferior to other bariatric surgeries. However, clinical utility of LMGB needs to be further validated by future prospective randomized controlled trials.

Is acetylation a metabolic rheostat that regulates skeletal muscle insulin action?

Skeletal muscle insulin resistance, which increases the risk for developing various metabolic diseases, including type 2 diabetes, is a common metabolic disorder in obesity and aging. If potential treatments are to be developed to treat insulin resistance, then it is important to fully understand insulin signaling and glucose metabolism. While recent large-scale "omics" studies have revealed the acetylome to be comparable in size to the phosphorylome, the acetylation of insulin signaling proteins and its functional relevance to insulin-stimulated glucose transport and glucose metabolism is not fully understood. In this Mini Review we discuss the acetylation status of proteins involved in the insulin signaling pathway and review their potential effect on, and relevance to, insulin action in skeletal muscle.

Early improvement of postprandial lipemia after bariatric surgery in obese type 2 diabetic patients

BACKGROUND

Bariatric surgery (BS) is able to positively influence fasting lipid profile in obese type 2 diabetic patients (T2DM), but no data is available on the impact of BS on postprandial lipid metabolism neither on its relation with incretin hormones. We evaluated the short-term (2 weeks) effects of BS on fasting and postprandial lipid metabolism in obese T2DM patients and the contribution of changes in active GLP-1.

METHODS

We studied 25 obese T2DM patients (age = 46 ± 8 years, BMI = 44 ± 7 kg/m2), of which 15 underwent sleeve gastrectomy and 10 underwent gastric bypass. Lipid and incretin hormone concentrations were evaluated for 3 h after ingestion of a liquid meal before and 2 weeks after BS.

RESULTS

After BS, there was a significant reduction in body weight (p < 0.001), fasting plasma glucose (p < 0.001), fasting plasma insulin (p < 0.05), HOMA-IR (p < 0.001), and fasting plasma lipids (p < 0.05). The meal response of plasma triglycerides, total cholesterol, and HDL cholesterol was significantly lower compared to pre-intervention (p < 0.05, p < 0.001). In particular, the incremental area under the curve (IAUC) of plasma triglycerides decreased by 60% (p < 0.005). The meal-stimulated response of active GLP-1 increased, reaching a statistical significance (p < 0.001).

CONCLUSIONS

BS leads to an early improvement of fasting and postprandial lipemia. The fall in fasting triglycerides is associated with an improvement of insulin resistance, while the reduction of postprandial lipemia is likely related to reduced intestinal lipid absorption consequent to bariatric surgery.

The Association Between Reduced Inflammation and Cognitive Gains After Bariatric Surgery

OBJECTIVE

Bariatric surgery is associated with improved cognitive function, although the mechanisms are unclear. Elevated inflammation is common in obesity and associated with impaired cognition. Inflammation decreases after bariatric surgery, implicating it as a possible mechanism for cognitive improvement. The objective of this study was to examine whether reduced inflammation is a possible mechanism for postoperative cognitive improvement in bariatric surgery patients.

METHODS

Participants were 77 bariatric surgery patients who completed cognitive testing before surgery and 1 year postsurgery. Cognitive domains assessed were attention/executive function, language, and memory. High-sensitivity C-reactive protein (CRP) was assessed at both time points.

RESULTS

Patients exhibited preoperative cognitive impairment, although improvements 1 year postsurgery were seen in both attention/executive function (mean [M; standard deviation {SD}]baseline = 53.57 [8.68] versus M (SD)follow-up= 60.32 [8.19]) and memory (M [SD]baseline= 44.96 [7.98] versus M [SD]follow-up= 51.55 [8.25]). CRP was elevated at baseline and fell into the normative range postsurgery (M [SD]baseline= 0.9 [0.7] versus M [SD]follow-up= 0.2 [0.3] mg/dl). Preoperative CRP was not associated with baseline cognitive function (β values = -0.10 to 0.02) and changes in CRP also did not correspond to changes in cognition postsurgery (β values = 0.02-0.11; p values > .05 for all domains). A trend was detected for smaller improvements in memory among participants with elevated baseline CRP (>0.30 mg/dl) versus those with normal levels (group × time: p = .083).

CONCLUSIONS

Improvements in high-sensitivity CRP were not associated with postoperative cognitive benefits. Future studies are needed to explore other inflammatory markers and potential mechanisms of cognitive improvement after bariatric surgery, including improved glycemic control and neurohormone changes.

Metabolic Mechanisms in Obesity and Type 2 Diabetes: Insights from Bariatric/Metabolic Surgery

Obesity and the related diabetes epidemics represent a real concern worldwide. Bariatric/metabolic surgery emerged in last years as a valuable therapeutic option for obesity and related diseases, including type 2 diabetes mellitus (T2DM). The complicated network of mechanisms involved in obesity and T2DM have not completely defined yet. There is still a debate on which would be the first metabolic defect leading to metabolic deterioration: insulin resistance or hyperinsulinemia? Insight into the metabolic effects of bariatric/metabolic surgery has revealed that, beyond weight loss and food restriction, other mechanisms can be activated by the rearrangements of the gastrointestinal tract, such as the incretinic/anti-incretinic system, changes in bile acid composition and flow, and modifications of gut microbiota; all of them possibly involved in the remission of T2DM. The complete elucidation of these mechanisms will lead to a better understanding of the pathogenesis of this disease. Our aim was to review some of the metabolic mechanisms involved in the development of T2DM in obese patients as well as in the remission of this condition in patients submitted to bariatric/metabolic surgery.

Preserve common limb in duodenal-jejunal bypass surgery benefits rats with type 2-like diabetes

BACKGROUND

In order to understand the underlying mechanisms by which weight loss surgeries improve metabolic profiles in type 2 diabetes mellitus (T2DM) patients and to evaluate the relevance of the length of the common limb in modulating various aspects of metabolism, we performed regular duodenal-jejunal bypass (DJB) and long-limb DJB (LL-DJB) surgeries in Goto-Kakizaki (GK) rats and compared their effects on glycemic control.

METHODS

Male GK rats at 12 weeks of age were used for this study. Body weight, food intake, fasting glucose, glucagon-like peptide-1 (GLP-1) level, glucose tolerance, insulin sensitivity, cholesterol and triglycerides levels, and fecal energy content were monitored for 26 weeks after the two types of surgeries.

RESULTS

We performed systematic analyses on GK rats after DJB or long-limb surgeries. Both procedures prevented body weight gain, reduced blood glucose and lipid levels, increased GLP-1 levels, and led to better insulin sensitivity. In general, LL-DJB displayed better effects than DJB, except that both surgeries caused similar increase in GLP-1 levels.

CONCLUSIONS

Both DJB and LL-DJB surgeries triggered beneficial effects in GK rats. LL-DJB showed better outcomes than DJB, which may be due to reduced food intake and higher fecal energy content. This indicates that the length of the common limb could influence metabolic profiles of surgery recipients.

Metabolic surgery, weight regain and diabetes re-emergence

INTRODUCTION

The poor success of clinical treatment of Type 2 Diabetes Mellitus (T2DM2) increased interest in metabolic surgery, which has been considered a promising alternative for the control of obese or non-obese diabetics. However, there is still no long-term follow-up to evaluate the duration of diabetes remission, and if weight regain would be associated to recurrence.

AIM

1) To describe the results of diabetic patients with a BMI < 30 and < 35 kg/m² submitted to the following types of metabolic surgery: ileal interposition and sleeve gastrectomy, Roux-en-Y gastric bypass (RYGB), adjustable gastric banding, duodeno-jejunal exclusion and duodeno-jejunal bypass; 2) to evaluate the possible relapse of diabetes after occurrence of weight regain on long-term after bariatric surgery.

METHOD

An expositive and historical literature review about metabolic surgery in diabetic patients with BMI < 30 and < 35 kg/m² was conducted, and systematic review of the association between disease relapse and weight regain after bariatric surgery.

RESULTS

After analysis of 188 published papers on Medline until 2010, three papers were selected, which included 269 patients who underwent RYGB. Pre-operatory BMI was between 37 and 60 kg/m² and follow-up of three to 16 years.

CONCLUSIONS

1) Two studies showed association between weight regain and recurrence of type 2 diabetes, while the third did not show this association when comparing groups with and without weight regain; 2) metabolic surgery has shown adequate control of T2DM2 in class I obese subjects; however, the non-obese group still need a long-term evaluation, considering the risk of diabetes recurrence when after weight regain.

Mechanisms of type 2 diabetes resolution after Roux-en-Y gastric bypass

BACKGROUND

Bariatric surgery is the most effective treatment for the reduction of weight and resolution of type 2 diabetes mellitus (T2 DM). The objective of this study was to longitudinally assess hormonal and tissue responses after RYGB.

METHODS

Eight patients (5 with T2 DM) were studied before and after RYGB. A standardized test meal (STM) was administered before and at 1, 3, 6, 9, 12, and 15 months. Separately, a 2-hour hyperinsulinemic-euglycemic clamp (E-clamp) and a 2-hour hyperglycemic clamp (H-clamp) were performed before and at 1, 3, 6, and 12 months. Glucagon-like peptide-1 (GLP-1) was infused during the last hour of the H-clamp. Body composition was assessed with DXA methodology.

RESULTS

Enrollment body mass index was 49±3 kg/m(2) (X±SE). STM glucose and insulin responses were normalized by 3 and 6 months. GLP-1 level increased dramatically at 1, 3, and 6 months, normalizing by 12 and 15 months. Insulin sensitivity (M of E-clamp) increased progressively at 3-12 months as fat mass decreased. The insulin response to glucose alone fell progressively over 12 months but the glucose clearance/metabolism (M of H-clamp) did not change significantly until 12 months. In response to GLP-1 infusion, insulin levels fell progressively throughout the 12 months.

CONCLUSION

The early hypersecretion of GLP-1 leads to hyperinsulinemia and early normalization of glucose levels. The GLP-1 response normalizes within 1 year after surgery. Enhanced peripheral tissue sensitivity to insulin starts at 3 months and is associated with fat mass loss. β-cell sensitivity improves at 12 months and after the loss of ≈33% of excess weight. There is a tightly controlled feedback loop between peripheral tissue sensitivity and β-cell and L-cell (GLP-1) responses.